Chemical Formula: CaF2
Mohs Hardness Scale: 4
Fluorite crystals are pretty simple, chemically speaking. They’re just fluoride and calcium, which naturally make a colorless crystal. But when impurities get into the mix, these crystals can be a whole rainbow of colors. And that range of hues can be even more impressive when we factor in fluorescence.
Fluorescence is the thing that happens when a thing absorbs light that we can’t see, like UV light, and emits light that we can. It’s why your teeth might glow blue in a bowling alley. We use the phenomenon of fluorescence in research, in technology, and even in our homes, with fluorescent lightbulbs. And we only know about it because of fluorite! Which is why researchers named fluorescence after the mineral, as a sort of thank-you.